Process timer (CB21865E)

We found this timer for times of a few minutes in a 1974 Ferranti transistor manual. The relay is 37 mA sensitive type.

Audio Booster (CB7103E)
This circuit is from a Popular Electronics from the 90s. Its gain is 22 dB and can be used as a...
Multiplex with transistors (CB23845E)
This circuit was found in an article in Radio Electronics magazine from October 1962. At that...
Integrator (CB14104E)
This circuit can be implemented with other operational amplifiers. The formulas for calculating the...